As disclosed in Patent Document 1 listed below, a conventional hinge device of this type generally includes a housing-side mounting member to be attached to a housing and a door-side mounting member to be attached to a door. The door-side mounting member is rotatably connected to the housing-side mounting member via a first link and a second link. As a result, the door is rotatably supported by the housing via the hinge device.
Side plates are respectively formed in opposite side portions of the first link and the second link in directions of rotation axes of the first link and the second link. One end portions of the two side plates of the first link are rotatably connected to the housing-side mounting member via a first central shaft that passes through the two side plates of the first link. Similarly, one end portions of the two side plates of the second link are rotatably connected to the housing-side mounting member via a second central shaft that passes through the two side plates of the second link. It is to be understood that the first central shaft and the second central shaft are parallel to each other.
The hinge device further includes two torsion coil springs. The two torsion coil springs are disposed parallel to the first central shaft and the second central shaft and are arranged in a row. One end portions of the two torsion coil springs that are spaced from each other are respectively pressed against the two side plates of the first link. Thereby, the first link is rotationally biased. The other end portions of the two torsion coil springs that are adjacent to each other are respectively pressed against a portion near a central portion of the second link in an axial direction of the second central shaft. Thereby, the second link is rotationally biased. As a result, the door-side mounting member is rotationally biased by the two torsion coil springs via the first link and the second link.